Redline makes a full synthetic polyol ester 10W-60.
I bought some today for a 510SMR.
It is not motorcycle-specific but was specified as appropriate by Redline’s tech and is labeled for motorcycle and wet clutch use.
High levels of zinc and phosphorous but some moly friction modifiers.
My R6 didn't get along with Redline's 10W-40 automotive oil about five years ago (very narrow clutch engagement range and inadvertent lever pressure enough to release that was cured by switching to Mobil 1 motorcycle and then Redline 10W-40MC when it became available) so I’m a little wary of the clutch performance. I’ll know in a week or two how it behaves and update.
Redline does make motorcycle-specific 10W-40, 20W-50 and 20W-60.
Viscocities cSt @ 40C (104F) / 100C (212F)
Redline 10W-60 173 / 25.5
Redline 20W-50MC 138 / 18.6
Redline 20W-60MC 185 / 23.0
I don't know what the operating oil temperature for a Husky 510 is but I'd bet it's closer to 212F than 104F so the common 20W-50 alternative is looking a little thin especially considering a story that 10W-60 was developed in response to engine failures in a version of BMW's M3; a Band-Aid.

I finally got around to Loctiting the primary drive gear nut and installing a Thumpertalk MCCT.
As far as I can tell, with the engine running, the MCCT backed itself off to a point just before the telltale clacking "rocks in a can" that we're listening for when adjusting the MCCT. It makes sense to me that at that point there would be little or no tension on the cam chain nor pressure on the guides but I felt better about adding 1/3 turn on the adjuster.
Should I have left it alone at the point where the MCCT had backed off to which is probably where the "rocks in a can" stops or is it cool at 1/3 turn in from there where I'm absolutely certain that any hint of "rocks in a can" is gone?
Btw, thanks everybody who contributes to Thumpertalk, especially the DRZ forum. I have a feeling that without knowing about the glitches my DRZ would have been one to grenade sometime down the road.

Oh, yeah. If you truly do have a 120/60-17, give it away and get a 120/70-17. Much better feedback, at least on a sportbike and a DRZ400SM is way number (not # but more numb, htf do you spell that?) than an R6 so I'd think it would benefit even more.

Can you borrow a GPS to find your speed and calibrate from there?
Actually, you'll probably want to find distance. My SM-06 speedometer unit itself indicated 67 mph at a true 63.2 mph; ran the speedo on a drill press for an hour at 67 mph and the odometer increased by 63.2 miles.
I thought you had it but your math is off, too.
Think of fractions. 3/2 flipped (inverse) is 2/3. Then think of as decimals 1.5 (^-1) = .666. You wanted the inverse of 1.24 which is 0.806 not 0.76 or you could have divided 53.38/65.94 instead which equals 0.810.

120/70-17 is effectively the widest street or DOT race tire that you will find so you're already there. The DRZ-SM has a 3.50 wide rim just like 99% (100%?) of current sportbikes and race-ready supermotos.
The stock DRZ-SM rear rim is a 17 x 4.50. 150/60-17 is a good choice for the rear. I have a Continental Contiforce SM in that size. The DRZ-SM's 4.5 rear rim is plenty wide for it and it's far from chain rub.
I didn't consider for a second that I'd have a clearance problem with a 160/60-17 Racetec Drift slick that is in my garage waiting to be mounted. Again, the rim is wide enough and the chain is definitely more than 5 mm away with the 150/60-17 so it should be fine. I'll know in a couple of weeks.
Thumpertalk search should be a good resource. Try www.supermotojunkie.com and www.bayarearidersforum.com for more.
Worry more about buying the best tire for your use than the widest one. Almost anything will be better than the stock 208SMs.

For whatever it's worth, I measured some things when I removed the #100 p.a.j. last night:
The port in the airhorn (airboot adapter) that supplies the pilot air jet is larger than 3.93 mm (drill bits used as go/no go) so approximately 4.0 mm.
The port in the carburetor that is fed by the p.a.j. is, as far as I could tell with the carburetor within the frame, between 2.36 and 2.76 mm so educated guess 2.50 mm.
I didn't have anything close to the ID of the #100 p.a.j. but found that they are available in #45 - #150.
http://www.sudco.com/keihin_saj.html
Maybe someone will chime in with how Keihin jets are numbered but I do know that the most common numbering is either by ID in mm or by flow rate.
If Keihins p.a.j. are by ID then it seems that removing the p.a.j. entirely could be like fitting a #250 p.a.j.
I know that it is common practice and is effective but completely removing a jet that results in a void between a 4 mm port and a 2.5 mm port hole doesn't seem all that great.
If the #100 isn't going to get used anyway, wouldn't it be better to identify the ID of the passageway in the carburetor and drill the jet to match?

What exactly does the TPS do and affect?
I'd think that it'd influence the ignition timing in relation to the throttle position but on a DRZ-S/SM is it doing it more for emissions reasons or max power?
How does unplugging it completely affect the timing?
How does simply detaching it from the stock carb affect the timing? (TPS @ idle position).
How does locking it in the WOT position affect the timing?

IMO perceived quality will come from your earned reputation and not from a name that is intended to imply greatness.
High quality, knowledgeable, honest, fair, blah, blah, blah unless you are.
From what I've heard, Sisnero is those things.
I'd go with Sisnero's.